Factors influencing the blood and plasma copper levels of sheep in swayback flocks

An association between the concentration of copper in whole blood and haemoglobin type in sheep

In a genetically diverse flock of about 320 sheep a significant association has been found between the concentration of copper in whole blood and the haemoglobin type.

Sheep were bled on four occasions over a period of 1 year, with the flock mean concentration of copper varying between 53 and 96 fig per 100 ml whole blood. The copper concentrations in whole blood from sheep of haemoglobin type B exceeded those from sheep of type A by 9, 16, 15 and 15 fig per 100 ml on the four occasions respectively. The copper concentrations from sheep of type AB were 8, 11, 7 and 7 μg higher than those from type A.

Differences in the frequency of the three haemoglobin phenotypes accounted for part of the breed variation in copper concentration previously observed in the same flock, but even when that effect was allowed for, highly significant breed variation remained. When plasma instead of whole blood was examined in two other flocks from which breed variation in plasma copper concentration had been reported no association was found between the plasma copper concentration and haemoglobin type.

Trace element deficiencies and fertility in ruminants: a review

Various minerals (copper, cobalt, selenium, manganese, iodine, zinc, and iron) can influence reproductive performance of ruminants. Reproductive failure may be induced by deficiencies of single or combined trace elements and by imbalances. This review is focused on maladjustments of trace elements leading to impaired breeding performance. Opinion is diverse as to the existence of various reproductive disturbances from either a severe copper depletion or a marginal dietary copper deficiency. Field experience suggests that administration of cobalt to ruminants on cobalt-deficient diets improves their impaired breeding performance. Selenium infertility in ewes is more prevalent in some areas and in some seasons, but the actual cause of this malady and the continuing role of additional factors are unknown. Manganese is necessary for normal fertility in ruminants, and feeding low-manganese rations depresses conception rates. Lack of iodine impairs thyroid activity and also ovarian function. Reproductive failure in the female and in spermatogenesis are manifestations of zinc deficiency. Despite forages rich in iron, low availability in certain instances could affect adversely ruminant reproduction. Knowledge of biochemical dysfunctions from trace element deficiencies is essential to determine the role which trace elements play in fertility of ruminant animals.

Copper metabolism in pregnant and pospartum rat and pups

A detailed study was made of copper metabolism in rats during and after pregnancy and in the fetuses and pups up to the age of 6 wk. Maternal ceruloplasmin levels increase only briefly at the beginning of the third (and last) week of pregnancy. They then decrease to normal levels at term and decrease markedly in the early postpartum period. Bilary excretion of copper and 67Cu almost stops at term and remains decreased for 2 wk. In spite of this, there is no increase in hepatic copper levels. Except for a 1- to 2-day period shortly after delivery, maternal rats have a positive copper balance if lacteal elimination of copper is ignored. Levels of copper in milk drop at about the fourth day postpartum. Fetal hepatic copper levels are already above adult levels, but the concentration almost doubles during the first week after birth; it decreases to adult levels by 6 wk of age. Ceruloplasmin levels, which are found to be very low in the pups at birth, increase sharply in the first 24 h and quickly achieve adult levels. Large quantitative differences also occur between the pups and adults in concentrations of copper in the brain and kidney. Qualitative differences, measured with 67Cu, are most notable when the neonatal liver is compared with the adult liver.